1. Field of the Invention
The present invention relates to an alternating voltage output apparatus and a vehicle including such an alternating voltage output apparatus. Particularly, the present invention relates to an alternating voltage output apparatus incorporated into a hybrid vehicle, an electric car, and the like, generating alternating voltage for commercial power supply to provide the generated alternating voltage to an external load, and a vehicle including such an alternating voltage output apparatus.
2. Description of the Related Art
Japanese Patent No. 2695083 discloses a motor drive and power processing apparatus employed in a vehicle that is driven by electric power. The motor drive and power processing apparatus includes a secondary battery, inverters IA and IB, induction motors MA and MB, and a control unit. Induction motors MA and MB include windings CA and CB, respectively, in a Y-connection. An input/output port is connected to neutral points NA and NB of windings CA and CB via an EMI filter.
Inverters IA and IB are provided corresponding to induction motors MA and MB, and connected to windings CA and CB, respectively. Inverters IA and IB are connected parallel to the secondary battery.
When operating in a recharge mode in this motor drive and power processing apparatus, alternating current power is supplied across neutral points NA and NB of windings CA and CB from a single phase power supply connected to the input/output port via the EMI filter. Inverters IA and IB convert the alternating current power supplied across neutral points NA and NB into direct current power to charge the direct current power supply.
In the motor drive and power processing apparatus, inverters IA and IB can generate alternating current power having an adjusted sinusoidal wave across neutral points NA and NB and provide the generated alternating current power to an external apparatus connected to the input/output port.
The motor drive and power processing apparatus disclosed in Japanese Patent No. 2695083 is not convenient, however, since the user cannot identify at a position remote from the vehicle how much alternating current power is left to be supplied when the motor drive and power processing apparatus is generating and providing to an external apparatus the alternating current power.
In other words, when the alternating current power from the motor drive and power processing apparatus incorporated into the vehicle is used as an emergency electric power source for a domestic load, it is inconvenient for the user to go all the way to the vehicle to check the remaining amount of energy of the vehicle. If the user fails to check the remaining amount of energy, the undesired event of sudden blackout may occur, or the user may not be able to drive the vehicle by itself to the nearest fuel station.